A fiber-based mobile backhaul network will in the following also be referred to as mobile backhaul network. In a mobile backhaul network, the radio access nodes in a radio access network, RAN for short, are connected with nodes in a core network. The RAN is usually a distributed radio access network where the radio nodes, radio equipment controllers, REC for short, and remote radio units, RRU for short, are split apart and communicate over a fiber optic network. The fiber optic network connects the REC with the RRUs and is referred to as mobile backhaul network in the following.
Typically, the radio nodes are interconnected via the mobile backhaul network that comprises a point-to-point fiber topology, a point-to-multipoint fiber topology or a ring fiber topology. Currently, fiber optic networks have short fiber path distances. In future scenarios it should be possible to transmit over several hundreds of kilometres of fiber path and to provide services over the RAN even in case of a failure in the fiber optic network. Until now, there is no effective way of protecting the core network or central parts of a distributed RAN. Also there is the need for more robust RANs since current RANs do not necessarily show robustness while being flexible and simple.